


The Siren and the Ace

by C_Grayson



Category: Undertale
Genre: Multi, did someone say asexual pirate, no, okay, siren grillby, well i did this anyway
Language: English
Status: In-Progress
Published: 2016-04-23
Updated: 2016-05-02
Packaged: 2018-06-03 23:02:53
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 4,752
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6630595
Author URL: https://archiveofourown.org/users/C_Grayson/pseuds/C_Grayson
Summary: <blockquote class="userstuff">
              <p>Sure, living alone on an island off the maps doesn't leave Grillby with a lot of options, but he has a feeling he'd still pick the same jerk every time.</p>
            </blockquote>





	1. Prologue

Grillby watches cargo being moved onto the rocks. The crew works fast, eager to go.  
  
His palms and nape scream static and his soul is threatening to snap.  
  
They'll be off soon. He'll be alone now, hidden on an island off the maps.  
  
He shakes the captain's hand farewell, then they set sail and he is left behind.  
  
All he has is four crates on a windswept beach.  
  
He watches as they drift away, until they're seen no more and then, Grillby sings.  
  
He's free to hum, without the fear of hurting those who listen. And so, the static fades.

**Notes for the Chapter:**

> *Long, tired sigh.*
> 
> I've finally planned this fic out chapter by chapter. Time to start the fun part!
> 
> Go kick renwhit cause this is their fault. (And while you're at it read their sansby fic!)


	2. Chapter 1: Things are good for like, a solid 3 seconds

**Notes for the Chapter:**

> Renwhit beta read this and is a cool dude so read their things and shower them in praise and then come back here and read my less good thing and shower me also in praise please
> 
> warning for game level violence and mild disassociation. very hurt no comfort.

The wind had stopped a day ago. The sun had disappeared behind the clouds and fog, plunging them into an eerie twilight. The crew of the Violet was stranded on a ship that was drifting off course. Every wave that lulled against the starboard hull pushed them further from the main shipping lanes and into uncharted waters.

The fog was dense. They wouldn't see land unless it hit them.

Sans leaned over the railing, trying to catch a glimpse of the waves lapping below. The sea smoke was too thick to see anything, and so he moved on.

He sauntered around the edge of the deck. He'd been doing the loop for an hour now. Nothing new. Still no wind. Still no visibility.

But he was on watch, and "stand around and be awake" was one of the easier jobs he had. He regularly failed at it, but still.

"You up?" he called out to Burgerpants, sitting at the helm.

"Yup," came a bored reply.

Sans nodded, then remembered the cat couldn't see him and made a ridiculous face. Ha! Maybe the fog was good for something.

"I'm gonna go down and check on Paps," he said. "I'll be back up in a few."

"Whatever."

Sans had to admire his crewmate's zeal for doing nothing. He liked to think of himself as an inspiration, but BPants's prodigious apathy was almost more impressive than his own laziness.

Sans walked down the stairs that led below deck. They creaked, despite his soft steps.

He slipped into the pitch black bunk room he shared with his brother, Muffet, and Burgerpants. He could hear the clink of Papyrus hooking and unhooking the tiny metal puzzle Sans had bought him at a port that had been too sunny and too crowded.

"Doing okay?" he asked quietly, walking over and reaching up a hand to pat the blankets.

"Yes," stage whispered Papyrus. "Careful, Muffet is sleeping."

"Was," came a sleepy drawl from the other top bunk. "How does it look out there, short stuff."

"You're barely any taller than me," said Sans.

"Just a few inches."

"Exactly," said Sans.

"But I still am," she replied coyly.

Sans scowled dramatically. "Nothing new. Boring."

He could hear shuffling and suddenly there were far too many eyes glinting at him from the darkness. Sometimes he forgot that Muffet could still see perfectly fine below deck.

"It's not my shift yet, is it?" she asked.

"Nope."

"Oh thank the gods," she said happily, sinking down into her hard bunk. "I'm cozy."

Sans turned his attention back to Papyrus.

"Want to stay down here, or come up with me?"

He could hear Papyrus looking guilty. "If it's alright with you, brother, I'm going to stay down here."

"Course it is," said Sans. "Try to sleep."

There was a chorus of goodbyes as Sans left the room, sliding the flimsy door closed behind him.

Back on deck, he paced around awhile, doing his best to stay awake by humming to himself.

The moon was nearly hollow, not that it would've made a difference. The tight visibility made him feel claustrophobic. It was like the sky was crushing them into the sea.

"Still awake?" he called up to Burgerpants.

There was a groan in response.

Good enough for him.

Sans leaned against the railing and took a deep breath, trying to wake himself up with the sharp, salty sea air. It didn't work. He felt as foggy as the night.

When he'd accepted the job he'd thought it would be exciting. A pirate on the open seas, finding bounty and babes in equal measure! He'd soon realized that most of the time, he'd be in the captain's room reading charts or helping to repair cracks in barrels. The pay wasn't extraordinary, and his social circle left something lacking, but for the most part he and his brother were safe. That was enough.

A voice snapped his eyes open. He hadn't even realized he'd been drifting off.

"Yeah?" he asked. No response. "BPants, you up?"

Again, no response.

He could have sworn he'd heard a voice though.

Pushing off from the railing, he hopped up the stairs to the helm. BPants was awake alright. His ears were darted forward and he had a death grip on the railing, leaning half his body over the water.

"What is it?" asked Sans, stopping to stand beside him.

"Someone's singing," said the cat monster reverently.

"What?" asked Sans coldly.

"There's a voice, over there," he said, pointing out into the darkness. "Quiet, listen."

And so Sans was quiet, and the two of them stood together, waiting.

There it was again.

Sweet and smooth, the voice greeted them like ripples on a pond. It dipped and swung, the colour of it unlike anything Sans had heard before.

Burgerpants's dropped his remaining hand from the railing. Sans looked up to see a vacant expression in his eyes.

"I have to get to the voice," he said.

Sans froze.

"I'm sorry?" he asked.

His crewmate didn't answer. Instead, with grace and speed Sans had never seen from him before, Burgerpants made a move to vault over the side of the ship.

There was a loud thump as Sans grabbed his soul and slammed him back onto the deck.

"What the hell?" he shouted.

Burgerpants squirmed and struggled. He hissed and kicked at the deck, yelling at Sans to let him go. Sans took a step back. Something about the sharp way he was moving and the frenzied look in his eyes. This was not the friend he knew.

The stairs thundered as Undyne and Papyrus burst onto the deck. Undyne already had a spear in hand, illuminating her face and making her vaguely visible through the fog.

"What's wrong? Did we hit land?" she demanded.

The voice. Burgerpant's reaction. Suddenly it clicked. Not fast enough, though.

"Get Papyrus below deck!" said Sans, not sure if he could hold two people down at once.

"What!?" shouted Undyne.

Sans looked down at her, his eye flashing blue. Hopefully she would be able to see him. "Below deck, please," he said, mustering as much calm as he could. "Siren."

A sickening splash told them that they were already too late.

Sans's grip on Burgerpants faltered for a second, but he tried to hold fast despite the awful tingling feeling in his bones. Papyrus had jumped. Papyrus had jumped.

That splash had been Papyrus and Papyrus couldn't swim and he was already sunk too deep by now for Sans to reach him and Sans had to keep holding down Burgerpants no matter how much he wanted to jump in. All Sans could do now is put his faith in Undyne. He had to stay here. He had to stay here he had to trust Undyne. Sans felt like he was going to throw up.

Muffet exploded onto the deck.

The women threw everything they had at each other, Muffet not seeming to care what damage she did. Undyne drove her back from the railing, only to be suspended in a web hastily cast between the rigging, deck, and railing, pulsing purple with magic. 

Sans reached out his other hand to press Muffet to the creaky boards. She was much harder to hold down than Burgerpants. Sweat beaded his brow as she screamed at the top of her lungs, begging for him to let her go. It was terrifying how fast she moved as she tried to claw her way back to her feet.

In the corner of his eye Sans saw Undyne jump overboard. Good. Good.

He strengthened his grip on Muffet's soul as she scrabbled against the deck. He had to duck a couple times to avoid spider attacks, but she was in no state to create something careful enough to pin him down. All he had to do was sidestep and he would be fine.

Burgerpants continued to fight him as well, thankfully without any magic.

It was exhausting holding two souls steady though, especially when the targets were trying to escape his grasp.

Sans's stomach dropped when Alphys waddled onto the deck. She was slower than the other had been. Sans's eyes widened as she deliberately walked towards the guard rail. Spreading his magic thin, Sans pressed her down as well.

Alphys didn't fight him as much. Small blessings.

And then, Nice Guy made his way up to the deck. He walked silently and with purpose towards the railing, and had already swung one foot over by the time Sans figured out how to hold four souls down at once. He felt the magic bubbling twisting in his soul, spilling out as blinding blue light from his eye. 

Muffet fought him every second, lobbing clumsy attacks whenever she had enough clarity of mind to realize he was the force pinning her. She screeched and screamed bloody murder. 

Burgerpants didn't seem to tire like he normally did. Sans could feel panic coming off of him in waves. Every once in awhile he would shout in frustration and claw at his chest. Sans winced. It was probably about as pleasant to be blue as it was to use it.

Alphys complained and groaned, trying to push herself up meekly. It was unsettling to see the doctor so dazed and vacant.

And finally, Nice Guy, squirming against the deck. He was silent. Sans could see the gears turning in his head, and sucked in a breath as Nice Guy reached for the knife in at his belt. Sans threw up a patch of searing blue bones. Nice Guy screamed twice, and then learned not to move.

Sans felt like he was going to throw up. This was too much for his soul. He could feel it quivering from the effort. If he could take a break, if he could just take a break for just a moment he would feel better. He couldn't, though. Muffet would bolt off the deck in a flash of arachnid speed.

Time slowed down. Or maybe it sped up. Vertigo dragged him to his knees, but still he held the others down.

Why wasn't Undyne back yet. How long had it been? What was going on?

He could feel his grip on the souls slipping. It was like trying to hold water. They were slipping through the cracks in his hands.

Muffet got lucky. With one shot she was able to reef one of Sans's arms to his side. It was at an agonizing angle, almost twisted out of the socket. Definitely dislocated. He screamed.

Alphys and Nice Guy were suddenly freed. Nice Guy rose to his feet and Alphys kneeled groggily.

Sans slammed them all back down, this time with half the control he'd had before. This was not good. This was not good at all. He was going to throw up. It hurt. It hurt a lot. He ground his teeth together and tried not to cry.

His head felt heavy on his shoulders. He could feel his focus fading. Like trying to run through sand. That's what this was like.

Undyne and Papyrus appeared on the deck. He wasn't quite sure how. He wasn't awake enough to care. All that mattered was that Papyrus was safe. Papyrus was safe.

Undyne tied him to the mainmast, then got started on Muffet. She gave Sans a weary glance, then added her own green magic to Muffet's soul, trapping her even more effectively.

Muffet scratched Undyne wherever she could reach. When Undyne wasn't careful, Muffet sunk her fangs into the captain's scaly skin. She twisted ear flaps and hissed with hatred, but eventually Undyne was able to tie all of her hands behind her back.

"Drop her," she said.

Sans blinked lazily. Undyne was watching him intensely. 

"Sans," she ordered. "Drop Muffet."

The meaning of the words slowly filtered into his skull. It took a moment to figure out which soul to drop. Sans let Muffet go.

Undyne dragged her to the mainmast and tied her up beside Papyrus.

They did the same for all the others. One by one, the demand on Sans's soul grew lighter. First, Alphys. Then Nice Guy. And then, finally, Burgerpants.

Sans winced as the strain was taken off. His soul felt wrong, like an elastic band that had been stretched too far.

His skull collided with the deck. He screamed, having fallen on the dislocated arm, then rolled so he could lie on his other side.

He felt heavy and drugged. His eyes slid shut. He willed them to open but found that he physically couldn't. His arms were so heavy. There was almost a comforting dullness to his senses. He felt trapped in the space right between and behind his eyes.

There was a vague sense of someone touching him, somewhere.

"Sans?"

He tried to form a voice, but his soul couldn't even do that.

Sans found himself fading, fading, f a d i n g  
 

**Notes for the Chapter:**

> honesly with how much research i did on whether bones sink i'm surprised the FBI hasn't busted in through my window


	3. Chapter 2: Things continue to be Bad

**Notes for the Chapter:**

> Thanks to renwhit for beta reading again! Go check out Ren's work (there's a sansby college au!!)
> 
> Sorry m'dudes, this isn't super long but it was one of those I-need-to-write-3000-words-before-I-get-to-the-good-stuff kinda things.
> 
> I would really really really love feedback on how I write Papyrus, he's a tricky character for me. Enjoy y'all~

Papyrus's soul had snapped back into awareness as he was sinking below the waves. His eyes and mouth had flown open to find that he was already water logged. He felt phantom touches across his bones as the current flowed through his ribs, brushing against his soul. It was so dark. It was so, so dark.

He’d panicked. He’d screamed and cried out for someone, anyone to help him. He kicked against the water, trying to push himself back up to the surface. His shoes and jacket made it hard to move. He felt heavy and useless and weak and sinking.

He'd felt the pressure slowly building. His soul was in a vice grip. His bones shuddered and creaked under the weight of the entire ocean above him.

He edged on hysteria. He was going to die, he was going to die, he was going to sink to the bottom of the sea and then he was going to die and he was never going to see his brother or Undyne again and how did this happen how did this happen—

Papyrus tried to clear his mind as his thoughts became increasingly frantic and negative. He could feel the edges of his form dissolving into the cold around him. He couldn't let that happen.

He’d closed his eyes; not like they could see much anyway. No point in scaring himself further. He’d tried to calm down. He had to stay hopeful. When monsters lost hope, they died. He’d repeated that mantra to himself over and over again as the waves had crushed his tiny frame.

When monsters lost hope they died.

When monsters lost hope they died.

When monsters lost hope they died.

And then he’d felt Undyne grab his wrist. She wrapped an arm around his waist, and they had rocketed up to the surface. He couldn’t remember having ever felt so relieved before in his life. He'd grabbed her soaked tank top, thanking all the gods he could name.

The pressure slowly lifted. Undyne held him tight. He felt himself solidify, his fingers slowly able to grip her shirt tighter.

And then, they'd broken the surface. Immediately, the song of the siren wormed it's way back into his soul. 

Next he knew he was waking up tied to a mast, Undyne standing nervously over his brother.

His brother, who wasn’t moving.

“SANS!”

Undyne had been right at his side.

“Are you okay, punk?”

She was already reaching to untie his hands.

“Is he okay!?” asked Papyrus, his voice edging on panic.

“Papyrus—“

“Is he okay?” His voice broke halfway through. Sans wasn’t moving. Sans wasn’t moving.

“I don’t know alright but once Alphys wakes up we can try and move him,” said Undyne. Her voice was softer than usual and deliberately slow. She was trying to calm him down. It was terrifying.

“Why can’t we move him now he’s—“

“He used too much magic Papyrus. His soul is sapped. I don’t know if that would dust him.”

Papyrus’s newly freed hands shot up to his mouth. His brother couldn’t die, Sans couldn’t die, what was he supposed to do if Sans died—

“Papyrus. Papyrus, stay with me okay?”

“What happened,” he asked in an uncharacteristic hoarse whisper.

“Siren. Didn’t bug me and Sans, but the rest of you tried to jump overboard. You…do you remember? I had to jump in after you.”

Papyrus’s shook at the flood of unpleasant memories. So that had really happened. It hadn’t just been a nightmare. It felt like a nightmare. More vivid, though. Realer. He had the soaked boots and clinging scarf to prove that it had really happened. Dear gods that had really happened.

“Anyway while I was getting you Sans held everyone else down and—“

“He can’t do that,” insisted Papyrus.

“Well, he did,” said Undyne. “And…it was just a little too much for him, I guess. So now he’s like this.”

“Oh my gods,” said Papyrus. “Undyne, Undyne I—“

“Don’t worry Pap. We'll figure this out, I just need you to stay here, okay?”

“Alright,” sobbed Papyrus weakly.

“Alright. I’m gonna check up on everyone else now.”

“Okay.”

Papyrus tried not to cry as Undyne untied his crewmates one by one. Everyone was groggy and couldn’t clearly remember what had just happened. She was gentle and kind. It was odd, but Papyrus supposed it was nice of her to at least try to be comforting.

Muffet held a hand to her head and wobbled a little as she stood up. She’d looked at Sans, and the web, and the odd way his arm was positioned. She'd then gone pale.

“Did I—is he—“

She hadn’t been able to finish the thought, and instead looked on in horror. She walked over and put a strong hand on Papyrus's shoulder. He'd caught her subtle flinch at the dampness of his jacket.

Alphys had teetered forward into Undyne's arms. For a few minutes sat and gazed around the deck, completely dazed.

Burgerpants had rubbed his wrists and walked up to the helm to watch the fog roll around them. He seemed nervous and scared. He darted around, checking ropes and sails that didn't need to be checked. Papyrus supposed he just needed something to do.

Nice Guy had immediately asked how he could help. Undyne had sent him to set up a bed in her room and he’d run off, only a little slower than usual.

Alphys had been coaxed over to Sans. She had Muffet dissipate the attack, and had Papyrus help her to lift up his brother's shirt so they could have a look at his soul. It had been dim. She made sure they moved him with the utmost of care.

After a quick examination of his bones—nothing bad except for a dislocated shoulder that she carefully snapped back into place—they moved Sans into the hastily made bed in the Captain’s room. It was big enough for Alphys to work in, and work she did, running half a dozen tests on Sans's soul and his bones.

The wind picked up, and Undyne got them sailing west. It took twice as long as usual to get everything set. No one was awake enough to do things properly and quickly. Papyrus’s hands shook as they raised the mainsail.

His brother was dying.

After Sans was settled and everyone else had gone back to bed, unnerved and exhausted, Alphys pulled him and Undyne aside. They stood in a circle outside the door to the room Sans was “sleeping” in. Papyrus couldn’t help but draw the comparison between Sans and monsters who had “fallen down.”

As the sun rose, a golden dawn breaking through the fading fog, Alphys explained it to them the best she could.

“So…y-your soul is basically y-you, right?” she started.

“Yeah?” said Undyne.

“Well, uh, if you uh, use too much magic—the energy comes from your soul—then that, uh, impacts everything. Not j-just conscious magic like attacks and speaking. So Sans used too much magic holding us all down, a-and now he needs to collect enough energy for his soul to uh, reboot. Sort of. I'm…not explaining this well,” mumbled Alphys. She rubbed an open palm against her forehead, eyes squinted in despair.

“It’s okay, we have time,” assured Undyne.

They exchanged a look. Alphys took a deep breath.

“O-okay, so your soul—it doesn’t have, uh, energy compartments for all the different things you do. It takes it all from the same, um, reservoir.”

“So if you empty the reservoir doing one thing—“ said Papyrus.

“—you empty the reservoir for everything else, too,” confirmed Alphys.

“So how long till it’s back up to normal then?” asked Undyne.

Alphys shrugged nervously. “I-I don’t know. A day? Two years? I-I’ve never seen anyone able to push themself so far before.”

Papyrus thought he was going to throw up. Two years. Two years without Sans.

“B-but he should do it. Eventually, yknow?”

Should. Eventually.

“Yeah, thanks Alphys. Go get some rest.”

The tiny doctor gave a tired smile and a casual salute before heading off for the bunks below deck.

Papyrus sullenly followed after her down the steps, ready to crawl into bed and sleep like the dead. He was so tired. His shoulders slumped and his feet dragged. Everything had been entirely too much.

He could deal with Sans in the morning. He was okay for now. Sans was okay for now. Papyrus just had to sleep, and then he could be there for his brother.

“Papyrus can you stay actually?” asked Undyne. It wasn’t really a question.

He stopped mid step and turned around, already feeling far too tired to even focus his eyes properly.

Undyne led him over to the railing.

They looked down at the sea for a few silent minutes. The waves churned as the Violet cut through the water. Papyrus’s scarf was still damp and clung to his jaw.

The waters seemed so much more threatening than before. For the first time it truly struck Papyrus that he wasn't able to swim and had put his faith in a shoddy, half-stolen half-improvised bowl made out of sticks.

Undyne tapped out a rhythm on the railing. She shifted awkwardly before looking at him cautiously.

“So…how are you.”

He raised an eyebrow.

It wasn’t often that they talked like this. Undyne especially never talked like this. She was strange. It must have shaken her up more than she had let on.

“I’m okay,” said Papyrus, looking down at the black waters hollowly.

“Liar,” accused Undyne.

“What am I supposed to say,” he asked, a little annoyed.

“Um, anything else? You almost died, Papyrus.”

“I thought we were talking about Sans.”

“We aren’t.”

He fell silent.

She waited for him as he turned over what he could possibly say to appease her in his head.

“I’ll be okay,” he said.

“Y’see, that’s not the same as being okay.”

“Undyne—“

“Look, I’m not that good with the whole ‘feeling' business, but if you need someone to talk to I’m around, okay? It's not good to bottle all of that stuff up.”

“Alright,” he sighed with frustration. He just wanted to sleep.

Undyne nodded, apparently satisfied, or maybe just too tired to press him further.

“Get some rest, kid.”

“Okay.”

“Goodnight, Papyrus.”

“Goodnight, Undyne.”

He could feel her watching him as he dragged his soggy boots down the steps.

*****

It took him two months. Two months to get “back to normal.” He still couldn’t use magic, and his fine hand coordination was shaky, but to anyone who passed him on the streets, Sans would appear pretty much as he always did. Maybe he'd seem tired, or they might wonder at the sling, but nothing would appear too out of the ordinary.

It had been slow.

Everything—from his eyesight to his balance to his ability to reason—had taken a serious hit. Sans didn’t even remember the first few weeks of his recovery, but apparently it hadn’t been pretty.

Papyrus still grabbed his arm when he stumbled, and Alphys still asked to see him daily.

He was trying hard to stay hopeful that everything would come back. Alphys said that that was the most important thing. He got tired easily, though. He knew that it took him longer to do things, even when Undyne insisted he was doing great. If he had to use one word to encompass himself, he would choose "lethargic." In his mind and body.

Muffet seemed especially nervous and guilty around him; he could tell because he didn’t get webbed for bad puns. Every once in awhile he caught her wincing at the sling his arm was still in. It was…a little uncomfortable. He wished she would just get over it. He’d even told her that. He missed the closest thing he had to a friend on this goddamn ship.

Sans had nothing to complain about. He was getting better.

Papyrus was the one to worry about.

Sometimes, Sans caught him looking out vaguely at the sea. Papyrus wouldn’t talk about it when he asked. He would pretend he was fine.

Sans knew he wasn’t.

He tried not to think about it. Tried not to think about the water sloshing into Papyrus’s skull, wrapping around his ribs. Tried not to think about Papyrus sinking deeper, deeper. Tried not to think about his brother coming out of the siren’s spell to find himself surrounded by water, the pressure slowly building. Tried not to think about how dark and cold it must have been.

Sans tried not to think about it.

He especially tried not to think about how Papyrus might be hiding things better than Sans thought, and that one day he would wake up and his brother would have faded to dust in the night.

Despite it all, Papyrus was there for him. Hope was important for monsters to heal, and so Papyrus did his absolute best to assure Sans that he would get better, that he would make a full recovery.

Sans wished he would stop with the “I’m fine” act for two minutes so they could actually talk. He was starting to understand why that answer always upset Papyrus so much. It was infuriating. He felt powerless and useless and like he should be doing something but he honestly didn't know what to do if Papyrus wouldn't talk to him.

Eventually, Sans made a decision.

Sans didn't mention it to anyone when he calculated where the island should be.

Sans didn’t mention it to anyone when he altered the route a little.

Sans didn’t mention it to anyone when he prepared himself for the jump, eating three servings of supper.

Sans didn’t mention it to anyone when he strapped a knife to his belt.

He wasn’t confident. He couldn’t even pretend he was doing this out of some twisted sense of responsibility to the safety of those who travelled the seas.

No, Sans wanted revenge.

He didn’t even know if he would be able to make the two shortcuts he would need to get to the island. His only previous attempt at a conscious attack had left him "slow" for days.

But that had been a month ago. He could do this now.

Hell, he had to do this. No fucking way did some creature get to mess with his brother and then walk away scot free.

It was late.

He didn’t have watch.

Sans whispered a goodbye to his brother, left a note under his pillow in case he didn’t come back, then snuck up onto the deck.

He managed to avoid Alphys and Nice Guy, creeping silently across boards, making his way to the back of the ship as they talked on the helm.

He looked out at his target. Open sky.

Sans cleared his mind.

He tried to suppress his fear, his worry, the creeping feeling that he was doing something very, very wrong.

He made the first shortcut.


End file.
